Abstract: A mobile gantry for transporting heavy loads includes first, second, and third booms which are supported on the ground by respective wheel sets. The booms are spaced from one another so to present a generally triangular configuration when viewed from above. First, second, and third lift legs telescope to extend and retract the booms, and the lift legs are interconnected to one another and can raise and lower a load. The load can be maintained level by individually adjusting the length of each boom by extending and retracting the lift legs. A pivot axle, attached to each one of the wheel sets, allows each of the wheel sets to pivot about an axis that is at least generally parallel to the ground, thus maintaining a uniform load while the mobile gantry encounters changes in slope or other surface irregularities.

Abstract: A extendible boom incorporates a locking mechanism that mechanically engages an extended boom section in response to the loss of hydraulic fluid pressure to the lift cylinder for that boom section so as to prevent unintended boom lowering. The locking mechanism includes locking devices, such as toothed cams, that are located on opposite sides of the boom and that are configured to move, 1) from a disengaged position permitting unobstructed movement of the extended section relative to the adjacent section, 2) to an engaged position in which the locking devices engage opposite sides of the extended section to prevent unintended boom lowering.

Abstract: An improved method of lifting a load includes supporting a load on a first section of an extendible lift assembly, the first section being surrounded by a second section, a hydraulic cylinder being operatively coupled to the first section so as to be capable of lifting the first section, and the first and second sections being supported on and vertically extendible with respect to a base. Then, while the load is supported on the first section, the hydraulic cylinder is extended to extend the first section relative to the second section and the base, thereby lifting the load to a first height. Then, the first section is secured to the second section so as to at least substantially prevent downward movement of the first section relative to the second section. The cylinder is then retracted and operatively coupled to the second section.

Abstract: A cask transporter for engaging, lifting and safely transporting casks containing nuclear waste material. The cask transporter comprises a gantry structure including a plurality of extendible telescoping boom assemblies coupled to a beam. A platform is coupled to and supports the gantry structure and couples the gantry structure to a driven tread mechanism. Couplers couple the beam to a cask to be transported, and cushioned restraints restrain a cask from colliding with the cask transporter.

Abstract: A gantry lift includes one or more pairs of vertically extendible lift columns and one or more horizontal lift beams supported across the upper ends of the lift columns. The lift beams are supported on header plates that permit slight pivoting or rocking motion between the lift beams and the lift columns. This helps counteract potentially destructive twisting or other forces that can result as the gantry operates and slight misalignments unavoidably occur. A half bearing between the header plate and the upper end of the lift column supports the weight of the lift beam and load and provides the desired pivoting action. The header plate and half bearing are secured to the top of the lift column by means of a full bearing positioned within the half bearing and secured to the lift column by a bolt or other fastener. Both the half bearing and the full bearing pivot around a common center.

Abstract: An apparatus and method for stabilizing a gantry. Powerful springs in the apparatus allow small deviations from a perpendicular configuration of a boom and beam arrangement. The springs resist larger deviations, thereby increasing the structural integrity and safety of the apparatus and method. The method stabilizes the gantry by providing a progressively increasing restoring force as the boom and beam travel farther from a starting position corresponding to a perpendicular relationship between the boom and the beam.